I have a sample express.js app:

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send(`<!DOCTYPE html>

<h1>My First Heading</h1>

<p>My first paragraph.</p>


app.listen(port, () => {
  console.log(`Example app listening on port ${port}`)

If I run this on localhost and open lighthouse tab in developer tools and measure performance I am getting FCP of 0.7 seconds for mobile (0.2 seconds for desktop).

Why is there such delay on localhost? Shouldn't it be almost instant?



Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.